Boulangerite - Encyclopedia

    Class : Sulphides and sulfosalts
    Subclass : Sulfosalts
    Crystal system : Monoclinic
    Chemistry : Pb5Sb4S11
    Rarity : Quite common


Boulangerite is a common sulphosalt of medium-temperature lead and antimony hydrothermal veins. It is found, like jamesonite, semseyite, zinkenite or plagionite, in dominantly stibnite veins invaded by lead fluids or in galena and sphalerite veins infiltrated by antimony fluids. It owes its name to the French mining engineer Charles Louis Boulanger who makes the first description of this mineral. Well formed crystals are very rare ; they are then prismatic and deeply striated longitudinally according to [001], sometimes acicular. Boulangerite occurs almost always in capillary fibers or fibrous masses, frequently asbestiform (variety "plumosite"). It is easily altered in surface giving mixtures of antimonyoxides and various oxides of lead. Its color is gray-black to bluish gray with a metallic luster. It is occasionally a lead ore. It is a mineral apreciated by mineral collectors but not easy to conserve due to its fragility

Boulangerite and pyrite from Noche Buena Mine, Zacatecas, Mexico
Boulangerite from La Mure Mine, Isère, France
Boulangerite and calcite from St- Pons, Alpes-de-Hte-Provence
Boulangerite from Wheal Boys, Cornwalls, England

Boulangerite in the World

Exceptional samples of the plumosite variety were discovered around 1940 in Pribram, Czech Republic ; they are acicular crystals up to 30 cm, the most beautiful specimens in the World. Beautiful centimetric crystallizations come from Trepca (Kosovo), Bottino (Tuscany) and Baia Sprie (Romania) as well as Swiss alpine clefts.

Boulangerite in France

In France, the most beautiful crystals come from the La Mure Mine in Isère with fibers of more than 5 cm as well as those of St-Pons which are taken in calcite and which after release with the acid can constitute spectacular samples. Boulangerite remains common in France, particularly in the auriferous veins of Labessette (Puy-de-Dôme) but also in the antimony mines of Haute-Loire (Ally Mine).

Twinning and special crystallizations

No twinning report for this mineral species.

Fakes and treatments

No fake inventories for this species.



Hardness : 2.5 to 3
Density : 6.2
Fracture : Undetermined
Trace : Gray



TP : Opaque
IR : -
Birefringence : -
Optical character : None
Pleochroism : None
Fluorescence : None


Solubility : Nitric and hydrochloric acid

Magnetism : None
Radioactivity : None

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